What one has paid knowing it not to be due, with the intention of recovering it back, he cannot recover back.

Explanation

(English-origin maxim.) One who pays money knowing it is not owed, intending to reclaim it, cannot recover — the voluntary payment with knowledge of the facts bars restitution.

Where this applies

• A man deliberately overpays his property taxes knowing the amount is wrong, planning to sue for a refund, but the court bars recovery because the payment was voluntary and knowing.
• A customer pays an inflated invoice on purpose, intending to demand restitution later, but the court denies the claim because she knew the charge was excessive when she paid it.
• A business makes an unnecessary payment to a government agency with the intent to reclaim it as a test case, but the court says a knowing, voluntary overpayment cannot be recovered.